Could someone explain returnless systems?

[demonpixel]

amx, i'll try to get you some pics of it on the car tonight. the return spring is still on the tang. to answer your question, with the car off and no linkage on, the secondaries DO snap shut when i let go after opening them.

just got off the phone with retrotek. they said that my vacuum is holding my secondaries open, and they said they are sending me a stiffer return spring and a phillips screw, and to uninstall the one that's one the tb now i need to undo the driver side phillips screw. that thing is on there TIGHT. they said to just use any means necessary to get it off, brute force, vise grips, etc. in the pics i'll post to you tonight, you'll see that i've already stripped it some.

they also said if getting the screw off doesn't work, they'll send me a new throttle body.

i'll keep ya updated, as always...